SU281497A1 - Method of obtaining low-carbon sponge iron or iron powder - Google Patents

Description

The invention relates to the field of direct iron production.

The known method of producing carbon-free sponge iron or iron and powder is iron, based on the reduction of iron ore material with hydrogen in a fluidized bed under pressure up to 40 MPa.

The disadvantages of this method are a reduction in the driving force of the process due to the intensive mixing of the solid and gas phases, fluctuations in the degree of utilization of the reducing ability of the gas and difficulties in operating the installation due to the unstable consumption of hydrogen.

To eliminate these drawbacks, a method is proposed for producing low-carbon sponge iron or iron powder, the aim of which is to achieve continuous process, ensure good contact of the heated reducing gas with the iron ore material, increase the utilization rate of hydrogen and, as a consequence, increase productivity and shorten the material processing time.

The proposed method is based on the forced filtration of a gas - a reducing agent through a layer of thin iron oxides. In this case, the gas is filtered in the direction perpendicular to the movement of the material in the reactor and does not interfere with its normal flow. Continuous movement of the material in the reactor occurs through gravity and is controlled by the discharge rate. FIG. 1 shows a schematic diagram

gas and solid material in the reactor, operating according to the proposed method, and FIG. 2 is a gas flow diagram in a gas installation with a two-zone reactor.

FIG. 1 and a part of a cylindrical peaKiiopa with a supply of heated reducing gas through a gas distribution device located along the vertical axis of the reactor. The gas distribution device is made in the form of cones,

mounted on a vertical pipe with a large number of large slits. Such a structure does not prevent the normal flow of solid materials and at the same time allows to reliably protect the gas distribution device from backfilling and clogging up with small particles of the charge. With a sufficient width of the internal cross section of the gas distribution device, the gas pressure over its height is small compared to

hydraulic resistance of the layer, and the uniform distribution of gas filtered through the layer depends mainly on the constancy of the thickness of the layer over the height of the reactor, i.e. the distance between the gas distribution. If it is necessary to pass through a layer in any part of it, more than in other areas, the quantity of layer in this area, and hence its hydraulic resistance, can be reduced by increasing the outer diameter of the gas distributor in this place.

The arrangement of the reduction front of iron ores in the reactor (conventionally shown in FIG. 1 point) depends on the speed of recovery of oxides and on the rate of descent of the material being recovered. At steady state, obviously, the position of the reduction front in the reactor remains unchanged. This allows the proposed process to be relatively easy to automate.

In the lower part of the reactor, due to the reduction of the crowd, the types of the layer of still perereagirovanny iron oxides using the reducing method, the gas is lower than in the upper part, therefore, the gases, waste w, ne, and pnzhnoy, after additional heating, , but in the upper part of the reactor.

The source of iron ore material is heated to 600-900 ° C. It is advisable to preheat the material in a separate unit, since in this case the process can be carried out in an oxygen-rich atmosphere with the best fuel utilization. Pagret iron material through the loading gateway 1 enters the reactor 2 of the filter layer, where it is subjected to the reduction of hydrogen-containing gas under pressure up to 40 MPa. During the reduction process, the solid material passes through zone A of the preliminary reduction of iron oxides and through zone B of the reclaiming process. The recovered material (iron powder) continuously enters one of two discharge gates 3 or 4. After purging with an inert gas, the iron powder is discharged from the gateway and sent either to the receiving hopper of the compressing unit (pressurized) in a protective atmosphere Ty Pyroforposti.

The circulation of gas is carried out as follows. The circulating compressor 5 supplies the hydrogen-containing gas to the heat exchanger 6, where the incoming gas is heated by the heat of the exhaust gas. Then, the reducing gas through the non-heater 7 (with electric heating or other heating) is supplied to the zone B of the reactor 2 and is filtered through a layer of the charge in the horizontal direction. From zone B, the gas is directed to heater 8, and from there to zone A of pre-reduction. From zone A, hydrogen, together with the resulting vapor reduction, is fed to heat exchanger 6, where it is cooled to 90-100 ° C. Next, the gas is injected into the desiccant 9. Due to the increased pressure, the desiccation of the gas takes place halfway.

After drying, the spin gas is sucked in by compressor 5 and the cycle is repeated. As hydrogen is consumed for the reduction of oxides, its volume in the system is continuously filled by supplying new norms.

Psycho-use for the reduction of iron oxides of hydrogen-containing gas makes it possible to obtain low-carbon iron powder or sponge iron suitable for casting special-purpose steel of responsible use in vacuum-produced induction furnaces.

The reduction process takes place under two gas conditions;

1) when the rate of horizontal gas filtration through a layer of singing does not prevent the continuous flow of the recoverable material;

2) when the gas filtration rate is high and there is no movement of solid material during gas filtration.

In the latter case, the transfer of solid material in the reactor is carried out in the following way.

The recovered product (using the unloading table, auger, or nasto through a hole) is continuously fed into one of the two lock vessels. In case of gas removal in horizontal direction from the cylindrical (working) part of the reactor to the final (zone B) material does not flow, therefore in it, due to continuous unloading, the moisture content of the material is formed. After a predetermined time interval, the automatically operating valve 10 and for a short time opens the gas line bypassing the circulating compressor 5, gas filtration through the bed is stopped, and the free cavity in Zope is filled with recovered material. Then the ventpl 10 overlaps the bypass (shown by the dotted line in the diagram), gas filtration begins through the bed and the cycle repeats.

For the purpose of dust removal, the layer of recoverable iron ore material is formed from particles of various sizes in such a way that the particle size of the gas blowing is increased.

Formula and 3 about b and e and

Claims (3)

1. The method of obtaining low-carbon sponge iron or iron powder from iron ore material with the help of hydrogen-containing-aza under pressure up to 40 atm, is excellent because, in order to increase productivity and reduce time processing of the material, interrupting the action of the force of tin the carp layer of predpravtelio pagreto up to 600-900 ° C iron ore material is blown with a stream of hydrogen-containing gas heated to 500–700 ° C in the direction unnatural to the movement of the material. 2. The method according to claim 1, characterized in that, in order to magnify the degree of utilization of the gas, it is heated through a layer of material in the final reduction zone, and then additional heating in the pre-reduction zone. 3. The method according to paragraphs. 1 and 2, characterized in that, in order to dampen the dust removal, the layer of iron ore material is formed from particles of different size, and in the direction of gas blowing, the particle size is magnified. Gas outlet Reactor vessel fpOHm reaction osstapay / geni Provision azo distribution singes and shi hi ,% 7/5 d; y; 7gAg / / f cone Understandable Shiite Lena Into the settled product ycmpoucrriL uz.J i -: -} f.psmaf  charge and melting Fresh feed / .. .2